#include "platform.h"#include "mp.h" // use extended gcd to find the multiplicative inverse// res = b**-1 mod mvoidmpinvert(mpint *b, mpint *m, mpint *res){	mpint *v; 	v = mpnew(0);	mpextendedgcd(b, m, v, res, nil);	if(mpcmp(v, mpone) != 0){		fprintf(stderr, "mpinvert: impossible\n");		exit(2);	}	mpfree(v);	mpmod(res, m, res);}